Pretensioned spring contact for cutouts



y 1951 w. o. SCHULTZ 2,555,153

PRETENSIONED SPRING CONTACT FOR CUTOUTS Filed March 14, 1947 INVENTOR.

Patented May 29, 1951 PRETENSIONED SPRING CONTACT FOR CUTOUTS William 0. Schultz, South Milwaukee, Wis., assi'gnor to McGraw Electric Company, a corporation of Delaware Application March 14, 1947, Serial No. 734,764

7 Claims.

This invention relates to a contact construction for cutouts.

This invention is an improvement over that disclosed in my prior patent, No. 2,357,772 of September 5, 1944, for Cutout Construction, assigned to the same assignee as that of the present application.

Objects of this invention are to provide a spring type contact construction for cutouts in which the movement of the spring is fully controlled both vertically and laterally, in which the pressure of the spring is not dependent primarily on the distance of movement during the closing stroke of the cutout but is controlled primarily by the initial tension imparted to the spring.

Further objects are to provide a spring type contact construction for cutouts in which a novel mounting of the spring is provided which adds to the flexibility of a spring contact of a given length and which, therefore, enables a shorter effective length of spring to be employed. This is especially desirable if heavy currents are carried by the spring.

Further objects are to provide a contact construction for cutouts which, though capable of use for any size of cutout, is nevertheless especially suitable for heavy duty cutouts as it provides an excellent contact not only with the movable portion of the cutout but with the stationary portion of the contact structure itself.

the accompanying drawings, in which:

Figure 1 is a side elevation partly broken away showing the upper portion of a cutout employing the novel form of contact construction.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Figure 3 is an enlarged line section on the line 3--3 of Figure 1.

Referring to the drawings, it will be seen that the contact construction is carried in any suitable manner, for instance by the upper end of the insulator I. This contact construction comprises a stationary portion indicated generally by the reference character 2 and a spring portion indicated generally by the reference character 3. The stationary portion 2 is provided with a base or rear portion 4 which is secured to the insulator in any suitable manner, for instance as shown in my above noted patent. It is provided with a line conductor receiving part 5 and with a guidin head indicated generally at 6 and shown in greatest detail in Figure 3. This guiding head is provided with a relatively wide lower portion 1 and a relatively narrow neck or upper portion 8 2 and with outwardly projecting rounded parts 9. The guiding head 6 also carries a transversely extending pin to which projects from opposite sides of the wider portion 1.

The spring portion of the contact structure comprises a generally U-shaped main body portion I! whose bail part [2 is pivotally supported by a lip 13 integral with the stationary member 2 and slightly bent upwardly rearwardly of the bail portion to loosely and pivotally retain the bail portion in place. It is to be noted from reference to Figures 2 and 3 that the main part or main arms H of the spring portion of the contact slightly clears the wider portion 7 of the guiding head 6 and consequently there is no friction as this portion of the spring contact moves up or down when the cutout is either closed or opened.

The main arms ll continue outwardly and are provided with downwardly curving shoulders 13 behind which the pins or projections E4 of the upper terminal l5 of the cutout is are adapted to normally seat. The downward pressure imparted to the arms H by means hereinafter described, thus provides a yielding locking of the cutout in closed position. The main arms ll continue forwardly and are divergent at their outer ends and curved upwardly as indicated by the reference character ll in Figures 1 and 2. The spring arms continue rearwardly by a pair of upper spring 53, all portions of the spring, it being understood, being integral. The spring arms l8 extend rearwardly and downwardly and are positioned below the rounded projections 9 of the guiding head 6.

It is to be noted particularly that these spring arms l8 bear not only against the projecting portions 9 of the guiding head but also bear against the neck or narrow portion 8 thereof. An initial tension is imparted to the spring so that the arms l8 tend to move upwardly and also tend to move inwardly. This provides a heavy contact pressure between the spring arms and the rounded projecting portions 9 and the narrow neck 8 of the guiding head 6 and thus affords an excellent electrical connection between the spring portion of the contact indicated generally at 3 and the stationary member 2.

It is to be noted that the pins IE! limit the downward motion of the arms ll of the spring member when the cutout is in open po The tension imparted to the spring port on of the contact is such that the major part of the downward pressure against the pins M is obtained from the initial tension imparted to the spring portion of the contact structure and only 0 a minor part of this pressure is due to the upward motion or" the arms II when the cutout is rocked to closed position. The heavy contact pressure is also transmitted to the arms ll and these arms are forced downwardly with heavy contact pressure against the pins or projections M of the cutout.

This'cutout may be either a drop-out fuse construction or a knife switch type of construction as shown in my above noted patent, and the term cutout therefore, is intended to cover any of the different types of cutouts.

It is to be noted that the relatively wide por tion I of the guiding head 6, though slightly out of contact with the spring arms ll, nevertheless controls the lateral motion or" the spring arms for they cannot be moved sidewise any material extent as they will immediately contact with the wider portion 1 of the guiding head 6.

Further it is to be noted that the stationary part 2 of the contact structure is also provided with a transverse web I9 which is positioned between the arms ll adjacent the bail portion and thus further assists in controlling lateral motion of the spring arms.

It will be seen that a novel form of contact construction has been provided by this invention in which movement of the spring is fully controlled and in which the spring pressure or contact pressure is primarily dependent on the initial tension imparted to the spring and is not primarily dependent on the distance of deflection of the spring when the cutout is closed.

Further it will be seen that this contact construction allows a shorter effective length of spring to be used though obtaining excellent flexibility and high contact pressure without any undue stressing or the spring part of the contact structurev This invention, therefore, lends itself readily to cutout structures in which heavy currents must be carried by the spring.

It is to be understood that although the contact construction has been shown as that for the upper end of a cutout, that nevertheless it could be used for both ends of the cutout, if so desired, as illustrated in my above noted patent. It is clear that if a drop-out fuse construction were used, only an upper contact construction, as described hereinabove, would be used, but where a switch blade was employed both an upper and a lower contact construction would be employed,

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. In a cutout having a movable member provided with contact means, a contact assembly comprising a stationary member provided with a guiding head, and a spring member having U-shaped arms supported adjacent their bail portion from said stationary member and located on opposite sides of said guiding head and arranged to engage the contact means of said movable member, said spring member having rearwardly projecting arms extending from the outer ends of said U-shaped arms and pretensioned for movement away from said U- shaped arms, and bearing portions carried by sad stationary member and arranged to restrain said rearwardly projecting arms against motion away from said U-shaped arms.

contact means of said movable member, said spring member having rearwardly projecting arms extending from the outer ends of said U- shaped arms and pre-tensioned for movement away from said U-shaped arms, and bearing portions carried by said stationary member and arranged to restrain said rearwardly projecting arms against motion away from said U-shaped arms,

3. In a cutout having a movable member provided with contact means, a contact assembly comprising a stationary member provided with a guiding head, and a spring member having U- shaped arms supported adjacent their bail portion from said stationary member and located on opposite sides of said guiding head and arranged to engage the contact means of said movable member, said spring member having rearwardly projecting arms extending from the outer ends of said U-shaped arms and pre-tensioned for movement away from said U-shaped arms, and bearing portions carried by said stationary member and arranged to restrain said rearwardly projecting arms against motion away from said U- shaped arms, said rearwardly projecting arms being also pre-tensioned for movement towards each other and being located on opposite sides of said guiding head and being arranged to grip said guiding head between them.

4. In a cutout having a movable member provided with contact means, a contact assembly comprising a stationary member provided with a guiding head, and a spring member having U- shaped arms supported adjacent their bail portion from said stationary member and located on opposite sides of said guiding head and out of contact therewith and arranged to engage the contact means of said movable member, said spring member having rearwardly projecting arms extending from the outer ends of said U-shaped arms and pre-tensioned for movement away from said U-shaped arms, and bearing portions carried by said stationary member and arranged to restrain said rearwardly projecting arms against motion away from said U-shaped arms, said rearwardly projecting arms being also pre-tensioned for movement towards each other and being located on opposite sides of said guiding head and being arranged to grip said guiding head between them.

5. In a cutout having a movable member provided with contact means, a contact assembly comprising a stationary member provided with a guiding head, and a spring member having U- .shaped arms pivotally supported adjacent their bail portion from said stationary member and located on opposite sides of said guiding head and arranged to engage the contact means of said movable member, said spring member having rearwardly projecting arms extending from the outer ends of said U-shaped arms and pre-tensioned for movement away from said U-shaped arms, bearing portions carried by said stationary member and arranged to restrain said rearwardly projecting arms against motion away from said U-shaped arms, and limit means for limiting 5 downward motion of said U-shaped arms when said cutout is open.

6. In a cutout having a movable member provided with a terminal having lateral projections constituting contact means, a contact assembly having a stationary member and a spring memher, said stationary member having outwardly projecting bearing portions, said spring member having U-shaped arms pivoted at their bail portion to said stationary member, said U-shaped arms being arranged to bear against the projections of said movable member and having means for interlocking with said projections, said spring member having rearwardly projecting arms connected with the outer ends of said U- shaped arms by means of loops, said rearwardly projecting arms being pre-tensioned away from said U-shaped arms and bearing against said bearing portions and. arranged to force said U- shaped arms against the lateral projections of said movable member when said cutout is closed.

7. In a cutout having a movable member provided with laterally projecting portions constituting contact means, a contact assembly comprising a stationary member provided with a guiding head and having bearing portions projecting from opposite sides of said stationary member and a spring member having U-shaped arms pivotally supported adjacent their bail portion from said stationary member and located on opposite sides of said guiding head and out of contact therewith and arranged to engage and interlock with the contact means of said movable member when said cutout is closed, said spring member having rearwardly projecting arms connected with the outer ends of said U-shaped arms by means of loops and pre-tensioned for movement away from said U-shaped arms and also pre-tensioned inwardly to grip said guiding head, said rearwardly projecting arms being arranged to engage said bearing portions and to thereby force said U-shaped arms into engagement with the projections of said movable member, said stationary member having a transverse web located adjacent the bail portion of said U-shaped arms and between said U-shaped arms, said transverse web and said guiding head jointly preventing lateral motion of said spring member.

WILLIAM O. SCHULTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 354,471 Hall Dec. 14, 1886 1,166,087 Schmidt Dec. 28, 1915 2,197,780 Anthony Apr. 23, 1940 2,357,772 Schultz Sept. 5, 1944 

